Recycling is a popular activity. Many people are trying to conserve natural resources and reusing components of products can help that conservation effort. That is one reason why many states have required deposits when purchasers buy beverages in aluminum cans and plastic bottles. The production of aluminum from bauxite is a very energy intensive process and recycling of aluminum cans becomes cost effective. Recycling of PET soda bottles is another area where recycling has been successfully applied.
Recycling PET bottles into carpet fibers are one area where recycling has achieved certain benefits. Besides reducing raw materials costs it has also reduced materials going into landfills. It is not uncommon for carpet manufacturers to use recycled two liter soda bottles in the production of polyester based carpet. PET polyester carpet is manufactured with yarn created from reclaimed polyester resins.
Post consumer carpet has not been an area where recycling has become wide spread. Post consumer carpet refers to carpet that has been installed in a house or office and is in need of removal so it can be replaced with new carpet or other types of flooring. Once the carpet installed in a house or office wears out, until recently the only destination for disposal of these carpets has been a landfill. Because of the type of ingredients used in carpet, i.e. thermoplastic polymeric materials, degradation in a landfill can take innumerable years. In addition, as landfill space has become scarcer and as petroleum based products have become more expensive due to the increase in petroleum costs and/or dwindling oil supplies, there has been an increasing interest in finding an industrial economical way to recycle post consumer carpets.
Carpets like many other composite materials are difficult to recycle effectively because they comprise a number of different materials that have been combined in a final article and it is difficult to separate out the composite into its individual components. This is important because the individual components have more value than as a composite. Carpets are comprised of a backing which supports and hold together a plurality of fibers that extend from the backing which form the pile or surface that is walked on by the user. An adhesive based material is typically used to secure the backing and the fibers together. Usually one type of polymeric material is used for the face fibers of the carpet and the backing uses another different polymeric material. In many carpets, this face fiber that makes up the pile may be a nylon, polyolefin a polyester etc. The backing is usually a polypropylene material although other materials may be used. In addition, the adhesive or other means to secure the fibers to the backing can be a third frequently different material. Because of the multiplicity of materials, carpet has been difficult to recycle into reusable individual components because the materials that comprise the carpet can not be readily or easily separated into the individual polymers. While there are some uses for composite polymeric materials, the value of the recycled post consumer carpet increases significantly if the components can be separated.
Some companies have resorted to burning the carpet as a source of heat instead of dumping it in a landfill because of the difficulties in separating the carpet components. In the burning method of recycling, typically the carpet is burned as a fuel and the heat is used to generate steam which can be used to generate electricity. The heat generated by the burning carpet can be used for other purposes as well. While this reduces landfill dumping, it is not really a satisfactory means of recycling the carpet materials. Another approach towards recycling can include melting the carpet instead of burning it and attempting to separate the components in the blend based on their melting or vaporization points. This type of process is energy intensive and requires complex equipment. This equipment must prevent the fibers from burning while they are heated to the proper melting temperatures to separate the components. Separating the melted carpet materials is not easily performed. Because of the difficulty in separating the components of a carpet into substantially uniform end products of primarily a single component, the recycled material is usually not used for new carpet but is rather used in such non-carpet products as park benches and other items where a blend of different polymers is not objectionable.